Some ground drilling or cutting tools comprise one or more cutting elements and it is desirable for those cutting elements to be replaceable. This enables damaged cutting elements to be replaced or worn cutting elements to be removed for re-work.
The working conditions for drilling equipment are exceedingly arduous and it is very difficult to construct drilling equipment so that the cutting elements are removable. The most reliable and easiest way of attaching cutting elements to a cutting tool is to fix them in place by welding.
For example, a cutting element may comprise a roller cone which is rotatably secured to an arm and the arm is in turn welded to the body of the drilling or cutting tool. A number of such cutting elements may be spaced around the periphery of the drilling or cutting tool.
Welding of the cutting elements to the cutting or drilling tool presents some difficulty in maintaining the cutting element. Massive rotary drilling tools can each have a large number of cutting elements that will each require, on a periodic basis, to be re-worked or replaced. Obviously, in the case of a welded cutting element, the re-working must occur with the cutting element in situ. Given that some drilling and cutting tools may be quite large, such an operation becomes quite a task.
In addition, when the cutting elements finally become unserviceable, then it is more likely for the drilling or cutting tool to be discarded in its entirety rather than attempting to rework the tool by removing cutting elements.
Accordingly, it is an object of this invention to overcome the abovementioned difficulties and to provide a means of attachment for cutting elements which enable convenient removal of the cutting element as and when required.